I've had lots to say about them over the years but since you asked, here are my thoughts again.
The Dash 8 is an excellent aircraft. It is ideal for routes under 90 minutes and it has served well on shorter Ontario routes to YYZ for about 20 years.
My beefs are with Jazz and the way it operates Dash 8s. The interiors of Jazz Dash 8s are awful. They are old and tired and add nothing to the comfort and enjoyment of a flight. In fact the opposite, I've been on the same aircraft twice in the last month which has unmaintained overhead panels which create an unbelievable noise volume on ascent. This particular plane is the worst I've experienced but it is a common problem.
Jazz have too many mechanicals delays. I've had two this year and more than I can remember in 2006.
The delays on arrival at the gates is ridiculous as the guy with the sticks to guide the plane to its final parking place is not there on arrival over 50% of the time. There are few things more annoying than flying into YYZ, maybe even arriving on time, and then sitting in an idling aircraft 50 feet from your final stop for 5, 10 even 20 minutes.
So, the Dash 8 is an excellent aircraft. If Jazz would give the commitment to interior rejuvenation AC is giving its domestic Airbus planes and if Jazz would provide the commitment to customer service AC offers on domestic routes where it faces competition, those of us who frequently fly the Dash 8 would start to receive something approaching value for the considerable money we pay to fly them.